An integrated circuit may contain a voltage protection structure connected to an input/output (I/O) pad of the integrated circuit, including a drain extended n-channel metal oxide semiconductor (DENMOS) transistor in a p-type substrate with a diode in series with the drain node of the DENMOS transistor. The anode of the diode is connected to the I/O pad. The source of the DENMOS is grounded. The diode combined with the transistor drain and the substrate may function as a silicon controlled rectifier (SCR) when an overvoltage occurs on the I/O pad, such as an electrostatic discharge (ESD) event, to raise the substrate potential of the DENMOS and so provide a low resistance path through the DENMOS from the I/O pad to ground. It may be desirable to increase the holding voltage of the protection structure while maintaining a desired trigger voltage. Increasing the lateral spacing between the diode and the DENMOS and/or increasing the area of the diode may increase the holding voltage, but will undesirably increase the area of the voltage protection structure.